There has been a growing number of companies that introduce smart devices such as smartphones or tablet terminals into their daily business operations. In conferences or meetings, attendees of the conference frequently capture images of notes written on a white board using their smart devices to send the captured images to their own personal computers (PCs) via mails.
Such image data taken by the smart devices such as smartphones are vulnerable to leakage. There is disclosed a related-art technology capable of deleting image data after the transmission of the image data to their PCs in order to reduce such divulging of the image data (e.g., Patent Document 1).
However, the image data taken by the tablet terminals or the like may still be liable to leakage. For example, when a wrong mail address is set for transmitting the image data taken by a tablet terminal via mail, the image data will be transmitted to the wrong address.